DESCRIPTION: (Investigator's Abstract): Neural mechanisms of human memory are investigated utilizing a unique opportunity, craniotomy where the patient is awake under local anesthesia for a portion of the operation. During the portion of these operation, neural activity occurring with memory measures is recorded by extracellular microelectrodes in human lateral temporal and entorhinal cortex, and hippocampus. Multiple aspects or memory are evaluated during those recordings, including long-term semantic, recent explicit post-distractional, working, and implicit memory and recall and recognition modes of retrieval. These various aspects of memory are assessed for three types of verbal material, visually presented names of objects and words and auditory words. based on our previous observation, we expect to identify neurons related to the various aspects of memory in lateral temporal cortex, as well as more medial temporal structures. Individual neurons will be related to a specific aspect of memory, and for the same aspect of memory, to a specific type of verbal material. Each aspect of memory for each type of verbal material has separate neural systems in temporal lobe. This study, then, will more clearly define the subdivisions of human verbal memory and establish some of the changes in neural activity occurring with them.